Tool-holding devices



A. B. CREED TOOL-HOLDING DEVICES May 26, 1959 2 Sheets Sheet 1 Filed Nov. 19, 1956 May 26, 1959 A. B. CREED TOOL-HOLDING DEVICES 2 Sheets-Shet 2 Filed NOV. 19', 1956 wwma QMJM ag v particularly to tool analogous purposes.

United States Claims priority, application Great Britain November 21, 1955 "4 c aims; (C1. 74-813 I This inventionrelates ito tool-holding devices and more Itis known to provide a tool post or tool box for a lathe in which provision is made to hold a plurality of tools and to rotate thetool post in, order to bring any into .workingposition. Thus, for eX Such a device means whereby the tool post may be locked very firmly in each of the selected positions. In one method an 1 operating handle is provided which moved in one direction, usually anti-clockwise, will release the post so that ,it can turn and will cause. engagement with, for example spring-loaded ball catches to causevth e whole post to rotate to a next working position; the return motion of j the handle is caused tolock the post in the selected position. The. locking action may be achieved byar ranging that the handle moves on a screw secured into the body of the lathe or to a slider on the lathe and when returned 'to its locking positionexerts, by reason of that screw, aclamping action, the tool post being held between the the movement of the handle to'the locking position causes pins in theztool postto enter holesin the body or slider ofthe lathe and thussecure thepostmore rigidly.. How; even-this method .is not wholly satisfactory because'not onlyis itnecessary to provide holessinx'the lathe or slider with which the pins can mate (so that the assembly of the device is a matter for great precision) but the pins tend to wear and thus, in due course, permit a degree of movement of the tool post even when it is in the locked position.

The present invention provides a novel construction of tool post in which a positive lock is provided without requiring modification of the lathe in any way and which automatically compensates for wear in the working parts so that any tendency for the post to develop any freedom of movement, so-called play, when in the locked position is reduced or eliminated.

A practical application of the present invention will now be described by way of example only with reference to the accompanying drawings whereof:

Fig. 1 is a side elevation of a tool post according to the invention,

Fig. 2 is an inverted plan of the tool post of Fig. 1,

Fig. 3 is a section on the line III-III of Fig. 2, and

Fig. 4 is a part-section in the line IV-IV of Fig. 2.

Referring to the drawings: the tool post comprises a body 5 which is rotatable about a threaded shaft 6 having a T-block or foot 7 for attachment to a lathe or other machine tool. The body 5 comprises a square posts for use on, lathes and for body of the lathe or slider and the said; ha'ndle. Since this does not afforda: sufiiciently'irigid T lock, however, proposals have been made to arrange that 2,887,904 1 i atented M rabies and a platform 9 carryingbolts 10. by which a tool ll can be clampedto the table 8, one toolextending along each side of the table, i.e. there are four tool positions. p M The shaft 6 extends through the body 5 ,(Fig. .3-) and ough the hub 12 of a hand lever 13 which is; provided to rotate the body about the; shaft for the tool-indexing purposes as later-described. i

.The hub 12 is screw threaded, at v14, tothe uppenpart of shaft 6 and it is arranged that between a lower. limiting position at which the hub engages body S-and an upper limiting position at which it engages a nut 15 the hub is permitted .one .complete rotation only, i.e.. corresponding to moving the four, tools to their indexing I positions.

The shaft 6 is integral with, carries,=a havabutments 17, the disc being re- .ceived in a recess in =the-body-5. .Each 'abutment has two faces, namely, a back face 27 and a front face-22.

Said recess also receivesa pivoted pawl 18 which is urged .;-by spring 13 to engagethe back face 27 of each abutmentv is urged by spring 21 to engage the front face 22 of 17.' Further, the body receives a pawl 20 which each abutment. j It will be noted from.Fig. 2-that face andthe face 22, with which-the face 23 w co-acts, arealso inclined that there is av wedging action 1 on engagement of said force of spring 21.

pawl with the face 22 undenthe 1 Pawl 20- is pivotally carried by a rod (Fig. 4)

,which also carries an arm 25 lying within-a recess in the upper, part of the body 5. The hub 12' is formed witha polygonal, plate-like member '26 (in this instance a square plate) which is rotatable within therecess 0n .adjustment of leverv 13 as' later described.- The arm .25' engages member 26 1 the armzis pushed away so that .upon rotation thereof from the member thereby to disengage pawl 20 from an abutment 17. Theparts 24,

25 and 26 pawL. I .w- Y.) a The bodyS has a pair of holes each of which receives comprise the means for releasing the second a spring plunger 27, the plungers engaging oppositefaces of the square member 26. The plungers permit limited movement of thehub 12. (and member 26) relatively plungers ,reach the limit of their outward movement and the plungers then-lock the/ member 26 to the body 5 'so that with, continued rotation of lever 13 thetbody is carried roundlwith it.

The limited relative movement-permitted; to member 26 is sufi'i'cient for said member toireleaserpawl. 20nfrom face 22 of abutment 17.

In use: when it is required to index the tool post the 13 is rotated (clockwise as seen in Fig. 2) and member 26 is turned relatively to body 5. Arm 25 engages a flat face of the member 26 and on such rotation the arm is carried outwardly so that pawl 20 releases face 22 of abutment 17. Thereupon with continued rotation of lever 13 the plungers 27 lock hub 12 to body 5 and the latter is carried round with the hub so that pawls 18, 20 ride past disc 16. When pawl 18 is brought past the next succeeding abutment 17 the pawl falls behind the back face 27 of the abutment. During this operation pawl 20 will have been continually held away from disc 16. The lever 13 is then rotated in the opposite direction bringing pawl 18 tight against the abutment and releasing pawl 20 so that the latter engages the front face 22. Due to the wedging action of pawl 20 and the face 22 the abutment is firmly held and thus the indexing operation is accurately performed.

As wear occurs between the pawls 18, 20 and the faces 22, 27 this is automatically taken up by the wedglash and play is eliminated.

It will be appreciated that substantial variations may bemade in the foregoing specific structure within the e scope of this -invention,- such alternative apparatus including-essentially the co-operating-fwedging and locking-- pawls asherein --described. Thus; any alternative means of causing the movement of the handle to engage --'to move thetool' box may be employed, for example springPloaded plungers or the like. Moreover, the handle maybesubstituted by a--control wheel, the tool box may have only two or three or may have more than -;four working positions and any alternativemeans may be adopted for releasing the -wedging -pawl.

I-claim: "1. A -tool' post comprising a body, a fixed threaded shaft about whichthe body 181 rotatable for'tool-indexing purposes-means for'rotatingthe body about the threaded shaft, an abutment on said shaft for each tool-indexing position each of saidabutments-having two faces, a

"--first-pawl to engage oneface of each shaft abutment to -1ock-the body against rotation in one direction, a second -pawl to engage the other;face of; each shaft abutment to lock the body against'rotation in the opposite direction and means for releasing the-second pawl to permit ---tool indexing rotation of the body, the co-acting'surfaces ofthe second pawl and each of said other faces of the -abutments being so-inclined that there is a wedging action on engagement of-the-secondpawl and the abutments.

2. A tool post comprising a body, a fixed threaded shaft about which the body is-rotatable for tool-indexing purposes, means for rotating the body about the shaft,

- an'abutment on theshaft for each tool-indexing position eachof said abutments having two faces, a first pawl to engage one face of each abutment to lock the body against a rotation in one direction,

'a-second pawl to engage the a "other face of each shaft abutment to lock the body against rotation in the opposite direction, means for releasing the second pawl to permit-tool-indexing rotation of the body-and an inter-connection between said releasing means and said body-rotating means which ensures that the releasing means is actuated before the rotating means,

the co-acting surfaces of the second pawl and each of said other'faces of the abutments being so inclined that there is -a wedging action onengagement of said second pawl and said-abutments.

3. A tool post comprising a body, a fixed threaded shaft about which the body is rotatable for tool-indexing purposes, means for rotating thebody about the threaded shaft, said means comprising a rotatable, polygonal, plate-like-member and a pair of plungersvspring-urged plungers being carried by to engage a pair of opposite faces of the member, said the body, the arrangement ment of rotation of said member and thereafter lock the member to the body, an abutment on the threaded shaft for each tool-indexing position each abutment having two faces, a first pawl to engage one face of each abutment to lock the body against rotation in one direction, a second pawl to engage the other face of each of said abutments to lockthe body against rotation in the opposite direction, means for releasing the second pawl to permit'tool-indexing-rotation ofthe body and an inter-connection betweensaid releasing .means and said body-rotating means which ensures that the releasing means is. actuated-before the rotatingtmeans, the co-acting surfaces of the second pawl and each of the other faces of theabutments being soinclined that there is a wedging action on engagement of the said pawl and said other face of the abutments.

4. A tool comprising a body, a fixed threaded shaft about which thebody is rotatable for tool-indexing purposes, means for rotating the body about the threaded shaft, said means comprising a rotatable, polygonal,

plate-like member and a pair of plungersspring urged to engage a pair of opposite faces of the member, said plungers being carried by the body, the arrangement being that the plungers permit limited relative movement of rotation of said member and thereafter lock the member to the body, an abutment on the threaded shaft for each tool-indexing position each abutment having two faces, a first pawl to engage one face of each abutment to lock the body against rotation in one direction, a second pawl to engage the other face of each abutment to lock the body against rotation in the opposite direction and an arm for rotating said second pawl and said arm engaging the polygonal member and .being adjusted thereby to release the second pawl from the other faces of said abutments during said limited v. relative movement of the polygonal member, the co-actingsurfaces of the second pawl and of the other faces of said abutments being so inclined that there is a wedgingaction on engagement of said pawl and said other faces of the abutments.

References Cited in the file of this patent UNITED'STATES PATENTS 

